La doping effect on TZM alloy oxidation behavior

• The oxidation can be resisted by doping La into TZM alloy.
• La doped TZM alloy has more compact organization.
• It can rise the starting temperature of severe oxidation reaction by more than 50 °C.
• Effectively slow down the oxidation rate.
• Provide guidance for experiments of improving high-temperature oxidation resistance.

Powder metallurgy methods were utilized to prepare lanthanum-doped (La-TZM) and traditional TZM alloy plates. High temperature oxidation experiments along with the differential thermal analysis were employed to study the oxidation behavior of the two kinds of TZM alloys. An extremely volatile oxide layer was generated on the surface of traditional TZM alloy plates when the oxidation started. Molybdenum oxide volatilization exposed the alloy matrix, which was gradually corroded by oxygen, losing its quality with serious surface degradation. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys has been enhanced, expanding its application range.